Mixing impellers



Sept. 11, 1962 F, E. BROWNING MIXING IMPELLERS Filed May 31, 1960 INVENTOR Frank E. Browning Fig.4

ATTORNEY S United States Patent Ofifiee 3,053,518 Patented Sept. 11, 1962 3,053,518 MIXING IMPELLERS Frank E. Browning, 4220 2nd Ave., Dallas, Tex. Filed May 31, 1960, Ser. No. 32,658 8 Claims. (Qt. 259-134) This invention relates to new and useful improvements in mixing impellers.

One object of the invention is to provide an improved impeller of such construction that the mixing, dissolving and dispersing of liquids and/ or other materials may be more efiiciently accomplished.

Another object of the invention is to provide an improved mixing impeller having vanes so arranged that the material is directed continually in opposite directions so as to thoroughly mix liquids and/or other materials having different specific gravities.

A further object of the invention is to provide an improved impeller, of the character described, wherein alternate vanes are inclined in opposite directions so as to impart alternate upward and downward movement to the material.

A particular object of the invention is to provide an improved impeller, of the character described, wherein the vanes are disposed in upper and lower pairs of inner and outer vanes with each pair of vanes being inclined in the same direction for imparting movement to the material in the same direction, the outer vanes having less inclination than the inner vanes whereby the material is fanned or spread axially or" the rotation of the impeller.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein an example of the invention is shown, and wherein:

FIG. 1 is a transverse, vertical, sectional view of a mixing vessel having an impeller constructed in accordance with the invention mounted therein and shown schematically, the relationship of the alternate vanes and the direction of movement of the material being shown in broken lines,

FIG. 2 is an underside perspective view of the impeller.

FIG. 3 is a plan view of the impeller, and

FIG. 4 is a transverse, vertical, sectional view, taken on the line 4-4 of FIG. 3.

In the drawings, the numeral designates a mixing vat or vessel which may be cylindrical and have a frustoconical, false bottom 11 or a conventional rounded bottom (not shown). An impeller 12 is suspended within the vat 10 on the lower end of an upright shaft 13 for rotation in a substantially horizontal plane above the bottom 11 and includes a fiat, thin body or plate 14 having a plurality of even-numbered, equally-spaced arms or blades 15 and 16. For mounting on the shaft 13, the plate 14 has a central opening 17 and a pair of diametrically-opposed openings 18 adjacent the inner ends of the arms 16. Although of identical shape, the opposed arms 15 are of reversed construction with respect to the opposed arms 16. Each arm has outwardlyconverging leading and trailing edges 19 and 20 and an outer end margin 21 which extends inwardly toward its leading edge at an acute angle to a radial line 22 extending through the center of the arm. As shown most clearly in FIG. 3, the leading edge 19 has greater angularity relative to this radial line 22 than the trailing edge 20.

The outer end margin 21 of each arm 15 is bent downwardly to form an outer, depending blade or vane 23, while the margin 21 of each arm 16 is bent upwardly to provide an outer upstanding blade or vane 24. An inner blade or vane 25 upstands from each arm 15 in spaced, substantially parallel relation to its outer vane 23, and identical inner blades or vanes 26 depend from the arms 16 in the same relationship to the outer vanes 24. The outer vanes are inclined outwardly and the inner vanes inwardly, with the inclination of said inner vanes being greater than the inclination of said outer vanes (FIG. 4). Although subject to variation, inclinations at angles of 30 and 20 relative to the vertical axis of the impeller 12 have been found to be most desirable. The vanes are of greater length than width, being of substantially the same length and Width, and extend inwardly at acute angles to their respective radius lines 22 whereby said vanes extend outwardly at acute angles from the path of rotation of their leading edges 19, preferably at 20. In addition to being flat and thin, the vanes are of appreciable width. As shown by the numerals 27 and 28, the leading edges of the outer vanes 23 and 24 are bevelled or sharpened inwardly and forwardly of said vanes and are swept back or inclined rearwardly at substantially the same angle as the inclination of said vanes, which is preferably 20. Identical leading edges 29 and 30 are formed on the inner vanes 25 and 26, but are inclined at an angle of approximately 30 or substantially the same as the inclination of said vanes. It is noted that the inner vanes extend from the trailing edges 20 of the arms and terminate short of the leading edges 19 thereof.

In operation, the vanes 23 and 25 coact to direct the liquids and/or other materials being mixed, dissolved or dispersed outwardly and downwardly as shown by the broken lines 31 and 32 in FIG. 1. Due to the greater inclination of the inner vanes, the paths of movement 32 of the material from said inner vanes are lower than the paths of movement 31 of the material from the outer vanes. This causes fanning or spreading of the material axially or vertically of the impeller 12. As shown by the broken lines 33 and 34, the material is directed outwardly and upwardly by the vanes 24 and 26 and the paths of movement 34 imparted by the inner vanes are higher than the paths of movement 33 imparted by the outer vanes because of the greater inclination of said inner vanes. The material is directed alternately downwardly and upwardly, since the inner and outer vanes have substantially common inner and outer paths of rotation and alternate vanes in each path of rotation have divergent or opposite inclinations. Due to this continual movement in opposite directions, the material is violently agitated so as to be thoroughly mixed in a minimum amount of time. Soluble solids may be rapidly dissolved and insoluble solids dispersed throughout the liquid. The sharpened leading edges 2730 strike the material at angles to the paths of rotation of the vanes so as to out said material with a slicing .elrect. Due to the angular relation of the vanes to their paths of rotation, the material is pushed outwardly as well as downwardly or upwardly by said vanes. Attention is directed to the fact that the outer vanes coact with one another and the inner vanes with one another to continually impart movement to the material in opposite directions axially of the impeller, whereby the material in a given area is directed or thrown alternately upward and downward. This violent agitation of the material results in continual movement of all of said material so that no portion thereof is trapped in eddies so as to remain substantially stationary.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the ap- 3 pended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A mixing impeller including a plate having a plurality of even numbered spaced arms, a plurality of outwardly inclined vanes upstanding from the outer ends of alternate arms, a plurality of outwardly inclined vanes depending from the outer ends of the other arms between the alternate arms, a plurality of inwardly inclined vanes depending from said alternate arms inwardly of and substantially parallel to the upstanding outer vanes, and a plurality of inwardly inclined vanes upstanding from said other arms inwardly of and substantilly parallel to the depending outer vanes, said vanes being substantially flat.

2. A mixing impeller as set forth in claim 1 wherein the inner vanes have greater inclination than the outer vanes so as to impart greater movement axially of the impeller to material than said outer vanes.

3. A mixing impeller including a substantially flat body, and a plurality of even numbered spaced inclined vanes extending from opposite surfaces of the body in alternate relationship, the vanes being disposed in pairs of substantially parallel inner and outer vanes on opposite surfaces of said body and having similar inclinations, each vane of each pair being inclined in a direction opposite to the corresponding vanes of adjacent pairs to impart movement to material in opposite directions axially of the impeller, said vanes being substantially flat.

4. A mixing impeller as set forth in claim 3 wherein the inner vanes have greater inclination than the outer vanes so as to impart greater axial movement to the material than said outer vanes.

5. A mixing impeller as set forth in claim 3 wherein the vanes of each pair are of different inclinations so as to impart different axial movements to the material.

6. A mixing impeller including a plate having substantially flat upper and lower surfaces, a plurality of even numbered spaced inclined blades upstanding from the margin of the upper surface of the plate, a plurality of spaced inclined blades depending from the margin of the lower surface of said plate between the upstanding blades, the depending and upstanding marginal blades having opposite inclinations to impart movement to material in opposite directions axially of the impeller, and a plurality of blades upstanding and depending from the upper and lower surfaces of said plate inwardly of said marginal blades, each of the upstanding inner blades and the adjacent depending marginal blade being substantially parallel and having similar inclinations, each of the depending inner blades and the adjacent upstanding marginal blade being substantially parallel and having similar inclinations, said blades being substantially flat and extending outwardly at acute angles to the paths of rotation of their respective leading edges.

7. A mixing impeller as set forth in claim 6 wherein the inner blades have greater inclination than the outer blades so as to impart greater axial movement to the material than said outer blades.

8. A mixing impeller as set forth in claim 6 wherein the blades of each pair of different inclinations so as to impart different axial movements to the material.

References Cited in the file of this patent UNITED STATES PATENTS 739,422 Jones Sept. 22, 1903 1,197,565 Taylor Sept. 5, 1916 2,235,604 Brumagim Mar. 18, 1941 2,651,582 Courtney Sept. 8, 1953 2,673,077 Messbauer Mar. 23, 1954 2,771,111 Seyfried Nov. 20, 1956 2,787,448 Fawcett Apr. 2, 1957 2,918,264 Ackles Dec. 22, 1959 FOREIGN PATENTS 1,204,172 France Aug. 3, 1959 

